There are breakdowns available. A lot of it depends on the agreement the developer has with the publisher, and with the systems it is being produced on.
Roughly 50% goes to the developer. The rest goes to:
- Publisher
- Marketing
- Console licensing fees
- Retail markup
- Packaging Fees & Distribution
Now, this can really vary, depending on contractual agreement. The publisher may be the developer (EA, Square Enix) which negates publishing costs. The developer may have an agreement with the console manufacturer to reduce costs for the licensing fees, or the console maker may pay for some of the marketing. Some games are digitally distributed, which contain no packaging fees and integrate other costs into the schema (such as licensing fees, retailer markup and licensing fees)
That is one reason why DD is so popular: the cut that goes to the developer is MUCH higher. Regularly, the dev may get 40-50% of the income from the traditional method (dev to publisher to retailer), whereas XBLA, PSN, WiiWare, Steam, and iPhope as well as the rest are quite a bit more lucrative.
In the end, you get (to devs)
Traditional: 40-50%
Steam: 60%
XBLA: 70%
PSN: 70%
WiiWare/VC: 70% (AFAIK)
iPhone: 70%
Which shows you why DD is becoming popular: with no middleman such as the store, the developer gets a much more lucrative deal.
Back from the dead, I'm afraid.